| Bison Steakhouse Huddersfield Limited | Hospitality | 2023 |
| Bite ME Films Limited | Professional & scientific | 2016 |
| Bizz Telecom Limited | Information & communication | 2006 |
| BJ Ellis Enterprises Ltd. | Wholesale & retail | 2024 |
| BJ Endo Ltd | Health & social care | 2026 |
| BJA Physiotherapy Ltd | Health & social care | 2012 |
| BJK FM Ltd | Professional & scientific | 2020 |
| BJK Global Consult Ltd | Professional & scientific | 2023 |
| BK Consultinguk Ltd | Extraterritorial | 2023 |
| BK Plumbing and Heating Solutions Ltd | Construction | 2021 |
| BK Trading Ltd | Wholesale & retail | 2023 |
| BK73 Ltd | Professional & scientific | 2022 |
| BKS Transport Ltd | Transport & logistics | 2020 |
| BL Gourmet Ltd | Hospitality | 2026 |
| BL Property Rentals Limited | Real estate | 2025 |
| BL Surveying Limited | Professional & scientific | 2023 |
| Black 5 Design Ltd | Administrative & support | 2007 |
| Black Bull Fitness Limited | Wholesale & retail | 2015 |
| Black Dyke Court (Holmfirth) Limited | Households | 2004 |
| Black FOX Hideaways Ltd | Construction | 2026 |
| Black Garter Investments Limited | Real estate | 2025 |
| Black Heritage Media C.I.C. | Information & communication | 2025 |
| Black Highlands Limited | Wholesale & retail | 2025 |
| Black House Salon Limited | Other services | 2019 |
| Black Kreative Ltd | Arts & recreation | 2022 |
| Black Pearl Retreat Limited | Hospitality | 2021 |
| Black Pulse Ltd | Wholesale & retail | 2026 |
| Black Sky Thinking Consultancy Ltd | Professional & scientific | 2022 |
| Black Snow Trading Ltd | Wholesale & retail | 2019 |
| Black Star Pubs (Vulcan) Limited | Hospitality | 2019 |
| Black Strategies Limited | Real estate | 2006 |
| Black-Oak Capital Limited | Professional & scientific | 2007 |
| Blackacre Estates Limited | Real estate | 2020 |
| Blackapple Solutions Ltd | Information & communication | 2020 |
| Blacker Road Cars Ltd | Wholesale & retail | 2026 |
| Blackforge Commerce Ltd | Wholesale & retail | 2026 |
| Blackhawk Aviation Ltd | Transport & logistics | 2024 |
| Blackleaf Financial Planning Ltd | Financial services | 2026 |
| Blackline Auto Ltd | Wholesale & retail | 2024 |
| Blackmoor Scout Ltd | Professional & scientific | 2021 |
| Blacknwhite Ltd | Administrative & support | 2023 |
| Blackrock HFD Limited | Wholesale & retail | 2019 |
| Blacksmith Group Limited | Construction | 2025 |
| Blacksmith Marketing Consultancy Ltd | Administrative & support | 2011 |
| Blackstar Publishers Ltd | Information & communication | 2016 |
| Blackstone Conversions Ltd | Construction | 2025 |
| Blackstone Properties HD Ltd | Households | 2023 |
| Blackstone West Yorkshire Estates Ltd | Real estate | 2018 |
| Blackthorn Consult Limited | Professional & scientific | 2017 |
| Blackthorn Lowloaders Ltd | Transport & logistics | 2004 |
| Blackthorn Private Ltd | Financial services | 2026 |
| Bladen Electrical Solutions Limited | Construction | 2026 |
| Blahaj Ltd | Professional & scientific | 2023 |
| Blair Finance Services Limited | Financial services | 2011 |
| Blaise Engineering Ltd | Professional & scientific | 2023 |
| Blake Clough Consulting Ltd | Professional & scientific | 2021 |
| Blake House Investments Limited | Construction | 2009 |
| Blaker Stone Masonry Ltd | Construction | 2012 |
| Blam Consulting Limited | Professional & scientific | 2021 |
| Blank Canvas Events Limited | Information & communication | 2004 |
| Blastsax Limited | Extraterritorial | 2015 |
| BLAUGRANA7 Ltd | Hospitality | 2025 |
| Blaze Customs Ltd | Wholesale & retail | 2022 |
| Blaze Interactives PVT Ltd | Wholesale & retail | 2023 |
| Blaze Trading Ltd | Wholesale & retail | 2020 |
| Blend Online Ltd | Professional & scientific | 2013 |
| Blended Academy Ltd | Other services | 2025 |
| Blended Ears Ltd | Information & communication | 2025 |
| Blended Hair Extensions Ltd | Other services | 2024 |
| Blenko IT Services Limited | Information & communication | 2008 |
| Blink Basket Store Ltd | Wholesale & retail | 2025 |
| Blittz Ltd | Real estate | 2023 |
| Blitzed by BEX Limited | Administrative & support | 2023 |
| BLM Digital Limited | Professional & scientific | 2020 |
| Blochaus Climbing Ltd | Arts & recreation | 2018 |
| Block 13 Ltd | Wholesale & retail | 2022 |
| Blockmed Pro UK Ltd | Information & communication | 2024 |
| Bloom Beds Ltd | Administrative & support | 2024 |
| Bloom Group International Limited | Arts & recreation | 2020 |
| Bloomindale Signature Florist Ltd | Wholesale & retail | 2017 |
| Blooming Surprise Ltd | Wholesale & retail | 2010 |
| Bloxco Holdings Limited | Financial services | 2019 |
| Bloxology Limited | Professional & scientific | 2021 |
| Blue Consultancy Ltd | Professional & scientific | 2016 |
| Blue HAT (2021) Limited | Professional & scientific | 2021 |
| Blue Innovations Ltd | Manufacturing | 2023 |
| Blue Maple Leaf Ltd | Wholesale & retail | 2022 |
| Blue Moon NDT Ltd | Professional & scientific | 2023 |
| Blue Panthar Sales Ltd | Wholesale & retail | 2025 |
| Blue Ribbon Investments Ltd | Real estate | 2025 |
| Blue Screen Limited | Manufacturing | 2016 |
| Blue Sigma Limited | Administrative & support | 2010 |
| Blue Spoon Consulting Limited | Professional & scientific | 2014 |
| Blue Star 200 Properties Limited | Real estate | 2023 |
| Blue Toko Consultancy Limited | Information & communication | 2016 |
| Blue Violet Limited | Wholesale & retail | 2023 |
| Blue Wisdom Limited | Information & communication | 2013 |
| Bluecap Limited | Transport & logistics | 2007 |
| Bluechip Holdings Group Limited | Wholesale & retail | 2023 |
| Bluelab Limited | Real estate | 2018 |